class TestClass():
    def __init__(self):
        self.a = 'av'
        
    def init(self):
        self.a = 'av init'
        self.b = 'bv init'
        
    def __str__(self):
        return f'TestClass(a={self.a}, b={self.b})'
        
if '__main__' == __name__:
    
    obj = TestClass()
    obj.init()
    print(obj)
    